Ultrasonic sensor assemblies are known and used in many different applications. Ultrasonic sensor assemblies are used, for example, to inspect a test object and detect/identify characteristics of the test object, such as corrosion, voids, inclusions, length, thickness, etc. In pipeline corrosion monitoring applications, the test object typically includes a metallic pipe. In such an example, a transmitter-receiver (“TR”) probe is provided for detecting/identifying the characteristics of the pipe. However a single TR probe occupies a relatively small area and, thus, has a relatively small testing range. Also, the pipe may have an arcuate contour surface. Detecting characteristics of the entire pipe with one TR probe can be inaccurate and time consuming. Accordingly, it would be beneficial to provide an ultrasonic sensor assembly that can address such issues. Further, it would be beneficial to provide this sensor array with a contoured shape that matches the shape of the test object.